In order to provide enhanced control of a clothes drying appliance, it can be desirable to know the moisture content of clothing being dried by a clothes dryer. For example, the dryer can be operated until it is sensed that the moisture content of the clothing has fallen below a desired amount. The heater or other appropriate components of the clothes dryer can then be de-energized or otherwise controlled accordingly.
Certain existing clothes dryers use two metal rods in parallel or a combination of rods and the drum surface as a sensor to detect available moisture in the clothing. Other sensors for detecting temperature and relative humidity can be added as well to sense internal air properties.
These sensors typically receive excitation power from the dryer control board via a physical connection such as electrical wires. Therefore, the sensors are placed on a non-rotating components of the dryer, such as the door or a fixed back wall. In some applications the sensors are mounted on a rotating surface and connected to controller using devices such as slip rings.
However, for many of such sensors, physical contact between the sensor and the clothes being dried is required for accurate sensor readings. Therefore, sensors positioned on the non-rotating components of the dryer, such as the door or a fixed back wall can have less frequency of contact with the entire clothing and do not provide consistently accurate readings.
In other words, because the clothing being dried is much less probable to contact the non-rotating components of the dryer than the rotating components, the non-rotating components represent a non-optimal positioning for the sensors. This problem is particular acute when the loads being dried are smaller loads (e.g. 2 to 5 pounds), very large loads (e.g. 12 pounds or greater) or loads containing clothes with large surfaces.
Therefore, clothes drying appliance systems featuring improved contact frequency between sensor and clothes are needed.